Method of packaging

ABSTRACT

A method of packaging steel and other articles wherein the articles to be packaged are first enclosed in a flexible sheet of material such as polyethylene and are then encapsulated in a cellular plastic sheath in a mold by placing a liquid foamable reaction mixture in the mold under confinement and at resulting conditions of elevated temperature and pressure. The flexible sheet enclosure is vented to atmosphere through the mold wall so that, as the foamable reaction mixture expands in the mold, there is no blockage by bubbles of air inside the flexible sheet enclosure.

United States Patent [15] 3,641,725

Grisell 1 Feb. 15, 1972 [54] METHOD OF PACKAGING 3,394,797 7/1968Flannigan ..53/46 FC [72] inventor: Richard T. Grisell, Terre Haute,Ind. Primary Examiner Theron E. Condon [73] Assignee: Polypac, lnc.,Terre l-laute, lnd. Assistant ExaminerNeil Abrams 221 Filed: Jan. 16,1970 worm-Mb Dewey [2]] Appl. No.: 3,546 [57] ABSTRACT Related US.Application Data [63] Continuation-impart of Ser. No. 847,921, Aug. 6,

I969, abandoned.

I $2] [1.8. (.l ..53/l4, 53/27, 53/36, 206/46 FC, 264/45 [51 l Int. Cl...B29d 27/00, 865d 81/12, 865d 85/68 [58] Field of Search ..53/27,36,170, 14; 206/46 FC; 264/41, 45

[56] References Cited UNITED STATES PATENTS 3,204,385 9/1965 De Remer etal ..53/27 A method of packaging steel and other articles wherein thearticles to be packaged are first enclosed in a flexible sheet ofmaterial such as polyethylene and are then encapsulated in a cellularplastic sheath in a mold by placing a liquid foamable reaction mixturein the mold under confinement and at resulting conditions of elevatedtemperature and pressure. The flexible sheet enclosure is vented toatmosphere through the mold wall so that, as the foamable reactionmixture expands in the mold, there is no blockage by bubbles of airinside the flexible sheet enclosure.

14 Claims, 13 Drawing Figures mimwrw 15 I972 3.641.725

sum 3 OF 3 INVENTOR. RlCH QRD T. CAUSELL BY MGM1LQM|M\X ATTORNEYS METHODOF PACKAGING CROSS-REFERENCE TO RELATED APPLICATIONS This application isa continuation-in-part of copending application, U.S. Ser. No. 847,921filed Aug. 6, 1969, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to a method of packaging. In a particular aspect, this inventionrelates to an improved method of packaging in a foamed cellular plasticto protect the contents of the package.

2. Description of the Prior Art Various procedures are known in the artfor encapsulation packaging such as for example as disclosed in the[1.8. Pat. Nos. to Freeman 2,895,603; Sterling 2,653,139; Chavannes etal., 2,524,162; Kishibay 2,516,124; Simon et al., 2,897,641; Schulz2,985,287; Simon et al., 2,780,350 and to Schneider 3,222,843. Theseprior art procedures are not always entirely satisfactory in allrespects and may be subject to one or more of the followingdeficiencies: first, rupture of the package or damage to the contents ofthe package upon rough handling; second, breaking through of thecontents of the package to damage other packages and articles beingshipped; third, incomplete enclosure of the articles being packaged; andfourth, adhering of the packaging material to the articles beingpackaged.

In general the first two of these disadvantages have resulted from lackof strength of the foamed plastic even though the package was placed inan outer carton or box to further protect it. The third disadvantagegenerally derives from an unsystematic procedure employed in injectingthe foamable plastic used for the encapsulation. Furthermore these priorprocedures have been generally applied to relatively small, easilyhandled articles. Accordingly a need has long existed for a method ofencapsulating articles in a cellular foamed plastic having sufficientstrength to protect the encapsulated article without the necessity of anexterior carton or box, and a procedure suitable for encapsulating evenvery large articles without the occurrence of voids.

SUMMARY OF THE INVENTION The present invention is an improved method ofpackaging articles in a rigid cellular plastic sheath by wrapping anarticle in a flexible sheet thereby forming an enclosure; sealing thesheet; placing the wrapped article in a mold; providing tear strips foropening the package, and encapsulating the article in a foamable,plastic-forming reaction mixture. The improvement of the presentinvention includes the steps of(a) placing a tubular vent, or pluralitythereof, in the mold with one end extending and terminating outside themold and the other end extending and terminating within the enclosureformed by the sealed sheet, and sealing the tube therein, (b) using apressure-resistant mold, generally but not necessarily, having twosides, two ends, a top and a bottom and having a plurality of air escapevents along the top of the mold, a plurality of closeable ports and ameans suitable for extending said tubular vent, or plurality thereof,and securely closing the mold, (c) introducing a foamable,plastic-forming reaction mixture into said mold through each of saidports, incrementally and sequentially, closing each port afterintroducing said mixture therethrough, and expanding said mixture underconfinement in said mold, whereby elevated pressures and temperaturesare obtained thereby, to cause said sheet to tightly surround saidarticle and to cause air within said sheet to be forced out of saidtubular vent and causing air in the mold to be forced out of the airescape vents; and causing said reaction mixture to form a solid, rigidcellular plastic sheath that surrounds said article to form anencapsulated article, (d) removing the encapsulated article from themold, and (e) removing the tubular vent, or plurality thereof, therebyforming an opening, or plurality thereof, in the sheath, and pluggingthe opening, or plurality thereof, thereby providing the packagedarticle.

The resulting foamed cellular plastic sheath exhibits a gradientstructure characterized by, in cross section, a tough, outer hide,followed by a region of high density adjacent thereto graduallydecreasing in density to a region of lower density adjacent thereto inthe center of the plastic, then a region of high density adjacentthereto and a tough inner hide adjacent to the flexible sheet whereinthe article is encapsulated. There is also provided a reinforcing meansand an encapsulating procedure which insures the elimination of voids.The method also provides for a rip strip for opening the package.

Articles packaged in the foregoing manner are protected from damage dueto rough handling, especially when the reinforcing means, as describedhereinafter, is employed. The method advantageously is employed forarticles weighing several tens Such articles can be handled by truckfork lifts, yard buggy, or crane with any type of sling or most lifts.When encapsulated within sufficient cellular plastic to insure buoyancy,the article, particularly a large one, can even be unloaded into theopen sea, where it floats. It can then be equipped with an outboardmotor, and directed to shore without the necessity of an auxiliaryunloading vessel or pier facilities. This advantage is obviously ofgreat value for areas having access to lakes and open sea but which aredeficient as to harbor and port facilities.

Objects of the invention are to provide an improved packaging method, toprovide a method of packaging which protects the contents of the packageas well as other goods surrounding the package during shipment, and toprovide a method of packaging which prevents the enclosing material fromadhering to the goods being packaged yet which permits a sturdyuninterrupted enclosure around the packaged articles.

Still another object is to provide a method of packaging an article in astrong, foamed cellular plastic which requires no additional outsidepackaging. Still yet another object is a method of packaging articlesvarying from small to very large without the occurrence of voids.

Other objects of this invention will be readily apparent to thoseskilled in the art from the disclosure herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2 and 3 are perspective viewsshowing initial steps in the process;

FIG. 4 is a perspective view of certain detail portions of the workpieceshowing a further step in the process;

FIG. 5 is a further perspective view showing another step in theprocess;

FIG. 6 is a sectional view taken through the mold used in the processshowing still another step of the process;

FIG. 7 is an enlarged top plan view of the mold with the workpiecetherein showing still another step of the process;

FIG. 8 is a perspective view of the mold showing a further step in theprocess;

FIG. 9 is a perspective view of the workpiece after it has been removedfrom the mold and showing still a further step in the process;

FIG. 10 is a view similar to FIG. 9 showing still another step in theprocess;

FIG. 11 is a fragmentary detail section of a tear strip forming a partof the package;

FIG. 12 is a fragmentary detail plan view of the structure of FIG. 11;and

FIG. 13 is a fragmentary view of an alternative form of the package ofthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now more particularlyto the drawings, there is illustrated in FIG. 1 an initial step in theprocess of packaging. The present procedure can be used to encapsulate aproduct which is fragile or nonfragile, large or small, or light orheavy. Assuming, for example, that the procedure is used to packagesteel used in building construction, a package might be created which isfor example on the order of l0 3 2 feet. In

FIG. 1 there is illustrated a sheet of polyethylene l resting upon asheet of reinforcing mesh 11. The strength of the reinforcing mesh 11 isdetermined by the material being packaged. In some applicationscardboard or light gauge steel might replace the mesh. Preferably,however, mesh greater than about %X% inch is employed and the preferredmesh is that known as burial vault mesh having apertures about l inch.The fencing material known as chicken wire is also suitable mesh. Anexample of unsuitable mesh is one having apertures less than %X% inch.It is not necessary that the apertures be rectangular nor that they haveany particular shape. In the present example the wire mesh used is inchheavy gauge.

Referring to FIG. 2, the products, article or materials to be packaged12 are placed upon the mesh 11 and the sheet along with a desiccant 15.When desired, the article is spaced from the mesh by one or moresuitable blocks placed between the polyethylene and the mesh to insurean adequate thickness of plastic beneath the article and to insure thatthe mesh will be about equidistant therein in the finished package. Theproduct is then wrapped as shown in FIG. 3 by surrounding the product 12with the polyethylene and sealing it. Sealing can be effected by use ofadhesive-coated tape or by heat sealing. The heat sealing procedure isillustrated in FIG. 4 and can be accomplished by a commerciallyavailable tool 16 which includes a pair of jaws 17 which are hingedtogether and can be closed against the polyethylene to seal it together.The jaws 17 may be coated for example, with an easy release materialsuch as Teflon which makes possible the fusing of the polyethylene butwhich permits easy release of the tool 16 from the fused togetherpolyethylene. It should be understood that in packaging, for example, aplurality of pieces of steel for use in a prefabricated building, thelongest and heaviest items making up the product, usually but notnecessarily, should be placed on the polyethylene first and the balanceof the items stacked on top. The use of the desiccant is for the purposeof preventing rusting of the materials and in some applications is notneeded.

Referring now to FIG. 5, the next step in the process is the insertingof a pair of tubes or hoses 20 (of at least 1 inch diameter in thepresent example) through the polyethylene 10, to provide for escape ofair. The diameter of the tubes may vary considerably, i.e., from aboutto about 10 inches, depending on the size of the article being packaged.For a small article the tube may conveniently be about inch insidediameter. For a very large package the hose may be as large as 10 inchesin diameter. The tubes are sealed in place by suitable tape 21 thusproviding venting of the interior of the package to the atmosphere.

The article is now placed in the mold, constructed as hereinafter setforth, which is lined with a suitable mold release agent, e.g., Pedaparpaper, polyethylene, or other suitable agent many of which are known. Asshown in FIG. 6, the placing of the tubes 20 through the polyethylene 10is accomplished in such a manner that he tubes 20 are projected throughthe sidewall 22 of the mold 25. The package enclosed in the polyethylene10 with the mesh 11 therebeneath is placed in the mold 25 on blocks 26which may be, for example, 2 inches square and formed of any suitablematerial such as wood, metal, glass, or polyurethane. It should beunderstood of course, that the wire mesh 11 can be placed in the moldinitially and the various steps illustrated in FIG. 15 can be performedin the mold 25 with the sides and top open or just the top open. Whenthe package is placed in the mold, it also rests upon reinforcing wiremesh 27 (of the same type as the mesh 11) as hereinbefore set forth,which is folded at a 90 angle as illustrated so that the lower leg 30 ofeach section of wire mesh is beneath the product while the upright leg31 of each section is alongside the product but positioned approximatelyequidistant between the wall of the mold and the wrapped article. Thereinforcing wire mesh 27 is similarly placed at the opposite ends of thepackage as well as on the longitudinally extending sides of the packagein most embodiments of the invention. When so located the same 90 L-shaped relationship is used, and the upright leg is placed aboutequidistant between the wall of the mold and the article. Inexperimental studies it was determined that sever damage inflicted onthe package caused at least partial destruction as far as the mesh, butthat surprisingly no damage was transmitted beyond the mesh into theinterior of the package. The damage-causing force was such that it couldnot have been withstood by either the mesh along or by the plasticalone.

Also shown in FIG. 6 are mesh sections 33 of reinforcing wire mesh alsoarranged at angle and nested over the junctions of the sides and top ofthe polyethylene enclosed product so that the upright leg is aboutequidistant between the side of the mold and the wrapped article.Sections 33, which are counterparts of mesh 27, are preferably employedwith very large articles and may be omitted when smaller articles arepackaged, as desired. It has been found that the top sections 33 arenecessary to the package when a crane is used to move the package bymeans of cable, chain, rope, etc. The sections 33 protect the contentsof the package even though the cable tends to cut into the package.FIGS. 6 and 7 also show 2 sheets 32 of wire mesh resting on top of thepolyethylene enclosed product. The sheets 32 are spaced from topsections 33 to provide for tear strips for opening the package. Theyprevent the package from puncturing when an item is dropped on thepackage or rupturing when it is lifted with a crane, fork lift truck orany type of lifting device. It is important that neither the sheets 32nor sections 33 cover the tear strips. Both the sheets 32 and the anglesections 33 should be taped to the polyethylene with sufficient slackthat when the foamable mixture is introduced, the mesh is maintainedapproximately equidistant from the top of the wrapped article and thetop of the mold. Otherwise the mesh will be horizontally displaced andwill float over the tear strips described hereinafter.

Referring now to FIG. 7, the top view of the mold, before the lid hasbeen put in place, shows that sheets 32 of wire mesh are preferably butnot necessarily (except for large packages) placed on top of the packageinside of and between, but not covering, tear strips 35 and 36 whichextend longitudinally and transversely of the package. The tear strips35 and 36 are provided by a flexible filament or line, e.g., a piece ofwire, rope or cable 38 which is secured to the polyethylene 10 by hightensile strength adhesive tape 38 and 39 in the manner illustrated inFIGS. 1] and 12. A preferred high tensile strength adhesive tape formost packages is filament tape manufactured by Minnesota Mining and Mfg.Co. The flexible filaments (or tear strips) 35 and 36 are arranged toextent outside of the mold 25 as shown in FIG. 7. As shown in FIG. 12tape 39 is wrapped around the portion of line 36 which extends from themold. The purpose of the tear strips 35 and 36 is for use in opening thepackage after it has reached its destination. The tear strip not onlytears through the cellular plastic sheath, but the adhesive tape alsotears the polyethylene 10 which otherwise is exceedingly difficult toopen after the encapsulating process.

It should be noted that except for blocks 26 and other possible spacersholding legs 31 in place, at least two inches of void is now presentbetween all planes of the polyethylene and the walls of the mold orfixture. When severe handling is anticipated, or buoyancy is desired,the void may be increased as desired, e.g., to l0, 18 or 24 inches ormore. The mold is closed securely as suggested in FIG. 8 for example bymeans of motor operated vertically movable connecting members 40 whichare operable to raise and lower the upper member 41 forming the topclosure member of the mold. The mold 25 should be of a constructioncapable of withstanding approximately pounds per square foot gaugepressure. Wood is a suitable material of construction but metal, e.g.,steel or aluminum, is preferred for assembly-line type of packaging. Arow of plurality of apertures 57 is provided along the length of thetop, generally at the axis, or approximately so; the apertures are of asize to admit an ordinary darning needle, e.g., apertures of aboutone-sixteenth inch diameter or less. After the mold release agent isinstalled in the top, a pricking means,

e.g., a needle or small drill, etc., is passed through each hole toprovide a plurality of punctures in the mold release paper, thusallowing the exit of air during the injection step. These apertures aresubsequently sealed by the foam. It will be noted in FIG. 8 that thetear strips 35 and 36 project from the mold, and a means is providedsuitable for extending the tubular vent, or plurality thereof, throughthe wall of the mold. Also in FIG. 8 it can be seen that there are anumber of ports 45 and 46 of about Vz-6 inches diameter positioned about12-24 inches apart, preferably about 18 inches, along the length at thebottom and along the top of the mold. These ports are provided with aclosing means (not shown), such as ball valves, gate valves, plug valvesor other suitable means, e.g., composition stoppers driven in tightlywith a mallet. These valves can be manually, electrically, orpneumatically operated. Each of these ports is provided with a sleeve 47by which means polyurethane or foamable polymeric material is introducedincrementally into the mold by any suitable means, e.g., a hose, orpiping. During the filling step, the hose should be inserted througheach sleeve a sufficient distance into the mold to discharge thematerial near the centerline of the mold. The sequence in which thefoamable reaction mixture is introduced through the ports into the moldis critical in order to eliminate voids and create the pressure andtemperature required to produce the density gradation which is animportant aspect of the present invention. Also, the increments, oramount, introduced into each port is likewise critical for theproduction of a satisfactory package. The amount is predetermined asfollows. The total amount of foamable reaction material used isdetermined by the required density, i.e., from 1.5 to 20 lbs. per cu.ft. of volume of void in the mold. About 60 percent of the total amountis injected in the bottom of the mold through the ports along the sideof the mold and 40 percent through the ports in the top. The rate ofpumping of reaction mixture is determined, from which can be readilycalculated the length of pumping time required to introduce the totalamount of reaction mixture. The time required to introduce eachincrement in each port is then determined accordingly. The hose or pipeis inserted first in the centermost sleeve 46A at the bottom of the moldand then in sequence toward the end of the package nearest thereto. Thenthe hose is returned to the next centermost sleeve and introduction ofreaction mixture is carried out sequentially as before. Next the hose ismoved to the centermost port on the top of the mold, thence to the end,as before; then the hose is returned to the next centermost port, andthence to other end. It is this pattern of introduction which is termedsequentially and incrementally." After each introduction of reactionmixture is completed in a respective sleeve, the hose is withdrawn andthe port is closed.

The foamable reaction mixture is in a fluid state as it moves into themold and upon entering and reacting in the mold it expands so as to fillall of the void within the mold to produce a rigid foam 48 completelysurrounding the polyethylene enclosed product. The temperature thereuponrises as a result of heat of reaction to about 100220 F. or higher. Thefinal pressure is created when the mold is filled with foam, the airescape exits are blocked by the polymer, and all ports have been closed.The amount of pressure so generated varies with the amount of foamablepolymeric material injected, as set forth above, but it generally variesfrom about 0.5- p,s.i.g., usually from 1 to 5.

The function of the tubes 20 is to vent the inside of the polyethyleneso as to prevent blockage of the polymeric material as it expands insideof the mold. Thus the venting of the interior enclosure of product makespossible the placing of a complete coating around the product ofapproximately a minimum of 2 inches and as much as 12 inches or more ofrigid foam polymeric material with all indentations and crevices in theproduct also having the rigid foam projecting thereinto.

Referring now to FIG. 9, the resulting package 50 is shown after removalfrom the mold. Projecting from the package are the tear strips 35 and 36as well as the tubes 20. The next step of the process is the removal,e.g., by cutting off, of the tubes 20 approximately 1 inch inside of thesidewall 0f the package 50. The final step is the sealing shut of theinside of the package by plugging and filling of the resulting openingsproduced by the removal of the tubes with a suitable plug, e.g.,additional polymeric material 51. Also the tear strips 35 should be cutoff flush with the outside surface of the foam 48 to prevent inadvertentopening of the package prior to its reaching its intended destination.

As mentioned the outside layer of the package 50 in the above embodimentcomprises a section of rigid foam material about 2 inches or more thick.Generally, this section must have sufficient structural integrity toadequately support the articles received in the package. This structuralintegrity is achieved by filling the mold under conditions ofconfinement and elevation of pressure, resulting in the gradientstructure described hereinabove. When desired, the outside of the moldcan be cooled by any suitable means resulting in a thicker out' sidehide.

Examples of polymeric materials which are suited for use as the rigidcellular plastic sheath in this invention include both homopolymeric andcopolymeric substances, such as poly aolefins such as polyethylene,polypropylene, polybutylene, polyisoprene and the like; preferablypolyurethanes such as are prepared from polyols and organicpolyisocyanates; and polystyrene, including polymers of styrene withmonomeric compounds such as acrylonitrile and butadiene. These materialsare producible from commercially available monomeric materials and theusual grade of commercial material is suitable for the practice of thisinvention. Also it is often possible to use off-grade materials.

A more preferred group of polymeric materials for use as the foam 48includes foamed polystyrene and polyurethanes. Thepolyurethane-producing reaction materials are particularly preferred.Foamable reaction mixtures yielding rigid, cellular plastics are wellknown in the art and any of these known foamable mixtures are suitablefor the practice of this in invention. If a particular mixture is notsufficiently exothermic to produce the preferred heating, a heatingmeans for the mold is employed.

A most preferred foamable polymer for use in accordance with thisinvention is polyurethane produced by mixing parts of a quasiprepolymerof tolylene diisocyanate and the propylene oxide adduct of sorbitol, thequasiprepolymer hav ing a free isocyanate content of about 30 percent;100 parts of a mixture of the propylene oxide adduct of sucrose indipropylene glycol, wherein the ratio of the sucrose adduct todipropylene glycol is 3 to 1; about 45 parts oftrichloromonofluoromethane; about one part of a catalyst which istriethylene diamine; and about 1 /2 parts of an oxyalkylene oxysiloxaneblock copolymer surfactant to regulate the cell size.

Polymeric materials as used in accordance with this invention contain ablowing agent which can be a gas or a compound which decomposes toproduce a gas, as is known to those skilled in the art.

Examples of suitable gases which can be used as glowing agents aretrichloromonofluoromethane, carbon dioxide, nitrogen, air, etc.

The process as taught in this invention is adapted to utilize a widerange of blowing agents; for example, blowing agents such asazobisformamide; azobisisobutyronitrile; diazoaminobenzene;N,N-dimethyl-N, N-dinitroso terephthalamide;N,N-dinitrosopentamethylenetetramine, benzenesulfonyl-hydrazide;benzene-l, 3-disulfonyl hydra zide; diphenylsulfon-3-3; disulfonylhydrazide; 4,4-oxybis benzene sulfonyl hydrazide, p-toluene sulfonylsemicarbazide; barium azodicarboxylate; butylamine nitrile; nitroureas;trihydrazino triazine; phenylmethylurethane p-sulfonhydrazide; andsodium bicarbonate.

It is to be understood that the above description relative to thepolymeric materials and blowing agents is not meant to be limiting.

In the case of heavy packages it is desirable to provide a means forremoving the package from the mold. Preferably the mold used has onesidewall which folds downwardly to permit ready access for removal ofthe molded product. Advantageously, removal can be facilitated bywrapping a pair of channels in polyethylene and placing them in thebottom of the mold but in spaced relation to the polyethylene coatedproduct. This spacing is obtained by the use of blocks such as 26. Theresultant product is illustrated fragmentarily in FIG. 13 wherein 48 isthe foam polyurethane, 55 are the channels, and 56 are the tines of theforklift truck. The channels can be used over and over with the mold andthe resultant grooves formed in the package can be used to receivematerial handling equipment between the source and destination of thepackage.

As mentioned hereinbefore, the outside of the mold can be cooled by anysuitable means resulting in a thicker outer hide. Many such means areknown, including use of a water-spray, a partial-immersion-water bath, awater jacket encompassing the mold or an environment of frigid air, andthe like. A waterspray is preferred.

The present invention produces a package which is water proof, vaporproof and shock resistant. The packages are also thief proof in thesense that any tampering therewith can be immediately ascertained.

I claim:

1. In a method of packaging articles by wrapping the article in aflexible sheet, sealing the sheet, thereby forming an enclosure placingthe wrapped article in a mold, providing tear strips for opening saidpackaged article, introducing a foamable, plastic-forming reactionmixture into said mold, expanding said mixture in said mold to causesaid sheet to tightly surround said article and to cause said reactionmixture to form a solid, rigid, cellular plastic sheath surrounding saidarticle, thereby forming an encapsulated article, the improvementcomprising the steps of:

a. placing a tubular vent or plurality thereof in the mold with one endextending and terminating outside the mold and the other end extendingand terminating within the enclosure formed by said sealed sheet, andsealing said other end of said tube within said enclosure.

b. using a pressure-resistant mold generally having two sides, two ends,a top and a bottom and having a plurality of air escape vents along saidtop of said mold, a plurality of closeable ports, and a means suitablefor extending said tubular vent or plurality thereof,

c. introducing said reaction mixture through each of said portsincrementally and sequentially, closing each port after introducing saidmixture therethrough, and expanding said mixture under confinementwhereby elevated pressures and temperatures are obtained, therebyforming said article encapsulated in a sheath, removing saidencapsulated article from said mold,

e. removing said tubular vent or plurality thereof thereby forming anopening or plurality thereof in said sheath and plugging said opening orplurality thereof, thereby providing said packaged article.

2. The method of claim 1 additionally comprising the step of securing aflexible line or plurality thereof to the said flexible sheet by hightensile strength tape prior to forming the plastic sheath around thesaid article to provide said tear strip or plurality thereof forremoving the sheath and said flexible sheet.

3. The method of claim 1 additionally comprising the step of placing areinforcing mesh sheet having apertures greater than about inch belowsaid flexible sheet prior to wrapping the article in the flexible sheet,so that said reinforcing mesh sheet is outside of the said flexiblesheet when the article is wrapped.

4. The method of claim 3 additionally comprising the steps of (a)placing blocks in said mold to support said wrapped article centrally insaid mold when the article is placed in said mold, (b) placing saidreinforcing mesh on said blocks and said wrapped article on said mesh,(0) extending the said reinforcing mesh upwardly around said article ands aced about equidistant from the wrapped article and the mol (d)placing an additional sheet of said reinforcing mesh or a pluralitythereof on the top of the said wrapped article and attached thereto byhigh tensile strength adhesive tape of a length sufficient to maintainsaid mesh about equidistant from the top of said wrapped article and thetop of said mold.

5. The method of claim 3 additionally comprising the step of securingtear strips in a rectangular pattern to the flexible sheet prior toforming the plastic sheath around the article for later removing thesheath, and prior to forming the plastic sheath around the article, thestep of placing a rectangular section of reinforcing mesh on top of thewrapped article in side of the said rectangular pattern so located asnot to cover said tear strips.

6. The method of claim 4 additionally comprising the step of placingadditional blocks between said mesh and said article thereby maintainingsaid mesh about equidistant between said article and said mold.

7. The method of claim 1 wherein said foamable plastic is a memberselected from the group consisting of polyethylene, polystyrene andpolyurethanes.

8. The method of claim 1 whereby the pressure resulting from saidconfinement within said mold is within the range of from about 0.5 toabout 30 p.s.i.g. and the temperature result ing from said reaction isin the range of from about to about 220 F. and said plastic sheath has agradient structure characterized by a tough outer hide, a region of highdensity adjacent thereto, a region of lower density adjacent thereto, aregion of high density adjacent thereto and a tough inner hide adjacentto said flexible sheet.

9. The method of claim 8 wherein said mold is cooled by a cooling meansto provide an exterior hide of improved toughness.

10. The method of claim 8 wherein said pressure is within the range offrom about i to about 5 p.s.i.g.

ll. The method of claim 1 wherein a first plurality of closeable portsof said mold are located along the length of and spaced upwardly fromthe bottom of said mold and a second plurality of closeable ports islocated along the top of said mold.

12. The method of claim 11 wherein said first plurality of ports arespaced l2-l 8 inches apart.

13. The method of claim 11 wherein said reaction mixture is introducedin a predetermined increment through each of said ports in a sequentialmanner starting at the centermost of said first ports, introducing saidpredetermined increment of reaction mixture therein and closing saidport, and sequentially and incrementally introducing reaction mixture ineach sequential port to the end of said mold, closing each port aftereach incremental introduction, then introducing said reaction mixture inthe next centermost of said first plurality and sequentially andincrementally introducing reaction mixture in the remainder of saidfirst plurality of ports and closing each port following each increment,and starting at the centermost port in the top of said mold, introducingreaction mixture sequentially and incrementally through each port to theend of said mold and closing each port after each of said increments,then introducing said reaction mixture the next centermost port andsequentially and incrementally through the remaining ports to the end ofsaid mold, and closing each port after said increment.

14. The method of claim 11 wherein said mold is cooled by a coolingmeans during the introduction of the reaction mixture.

2. The method of claim 1 additionally comprising the step of securing aflexible line or plurality thereof to the said flexible sheet by hightensile strength tape prior to forming the plastic sheath around thesaid article to provide said tear strip or plurality thereof forremoving the sheath and said flexible sheet.
 3. The method of claim 1additionally comprising the step of placing a reinforcing mesh sheethaving apertures greater than about 3/8 X 3/8 inch below said flexiblesheet prior to wrapping the article in the flexible sheet, so that saidreinforcing mesh sheet is outside of the said flexible sheet when thearticle is wrapped.
 4. The method of claim 3 additionally comprising thesteps of (a) placing blocks in said mold to support said wrapped articlecentrally in said mold when the article is placed in said mold, (b)placing said reinforcing mesh on said blocks and said wrapped article onsaid mesh, (c) extending the said reinforcing mesh upwardly around saidarticle and spaced about equidistant from the wrapped article and themold, (d) placing an additional sheet of said reinforcing mesh or aplurality thereof on the top of the said wrapped article and attachedthereto by high tensile strength adhesive tape of a length sufficient tomaintain said mesh about equidistant from the top of said wrappedarticle and the top of said mold.
 5. The method of claim 3 additionallycomprising the step of securing tear strips in a rectangular pattern tothe flexible sheet prior to forming the plastic sheath around thearticle for later removing the sheath, and prior to forming the plasticsheath around the article, the step of placing a rectangular section ofreinforcing mesh on top of the wrapped article inside of the saidrectangular pattern so located as not to cover said tear strips.
 6. Themethod of claim 4 additionally comprising the step of placing additionalblocks between said mesh and said article thereby maintaining said meshabout equidistant between said article and said mold.
 7. The method ofclaim 1 wherein said foamable plastic is a member selected from thegroup consisting of polyethylene, polystyrene and polyurethanes.
 8. Themethod of claim 1 whereby the pressure resulting from said confinementwithin said mold is within the raNge of from about 0.5 to about 30p.s.i.g. and the temperature resulting from said reaction is in therange of from about 100* to about 220* F. and said plastic sheath has agradient structure characterized by a tough outer hide, a region of highdensity adjacent thereto, a region of lower density adjacent thereto, aregion of high density adjacent thereto and a tough inner hide adjacentto said flexible sheet.
 9. The method of claim 8 wherein said mold iscooled by a cooling means to provide an exterior hide of improvedtoughness.
 10. The method of claim 8 wherein said pressure is within therange of from about 1 to about 5 p.s.i.g.
 11. The method of claim 1wherein a first plurality of closeable ports of said mold are locatedalong the length of and spaced upwardly from the bottom of said mold anda second plurality of closeable ports is located along the top of saidmold.
 12. The method of claim 11 wherein said first plurality of portsare spaced 12-18 inches apart.
 13. The method of claim 11 wherein saidreaction mixture is introduced in a predetermined increment through eachof said ports in a sequential manner starting at the centermost of saidfirst ports, introducing said predetermined increment of reactionmixture therein and closing said port, and sequentially andincrementally introducing reaction mixture in each sequential port tothe end of said mold, closing each port after each incrementalintroduction, then introducing said reaction mixture in the nextcentermost of said first plurality and sequentially and incrementallyintroducing reaction mixture in the remainder of said first plurality ofports and closing each port following each increment, and starting atthe centermost port in the top of said mold, introducing reactionmixture sequentially and incrementally through each port to the end ofsaid mold and closing each port after each of said increments, thenintroducing said reaction mixture the next centermost port andsequentially and incrementally through the remaining ports to the end ofsaid mold, and closing each port after said increment.
 14. The method ofclaim 11 wherein said mold is cooled by a cooling means during theintroduction of the reaction mixture.